Sensors for absolute position sensing are known in the art. U.S. Pat. No. 7,047,865 discloses a known sensor in which light from a light source travels through a first fiber optic array and is projected onto a pattern for illuminating the pattern. Light reflected off of the pattern passes through a second fiber optic array to a detector for detecting the illuminated pattern.
FIG. 10 illustrates an absolute position sensor 320 associated with a cylinder 322 for detecting a position of a rod 324 of a cylinder. The sensor 320 is affixed to a portion of a housing 328 of the cylinder 322. The rod 324 includes a predefined pattern 330, a portion of which is shown in FIG. 10, that extends under the sensor 320. The position of the rod 324 relative to the housing 328 is determined based upon the portion of the predefined pattern 330 detected by the sensor 320.